document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=762911>Question 762911</A>: <I><SPAN STYLE=\"word-break: break-all;\"> a wholesale poster company sells 20 posters for $12 and 30 posters for $15 the relationship between the number of posters sold and the cost is linear. find an equation giving the cost (c) in terms of the number of(n)posters </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #464293 by </B><A HREF=/tutors/aboutme.mpl?userid=malglu><B>malglu(63)</B></A><img src=\"/images/stars/stars-08.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=malglu><IMG SRC=http://www.algebra.com/images/aboutme-small.gif BORDER=0 alt=\"About Me\" VALIGN=MIDDLE></A>&nbsp;<IMG SRC=http://www.algebra.com/images/nopicture.jpg><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=464293\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> since the relationship is linear we know that we plot the relationship on a co-ordinate system.  we would have a line going through the points\r<BR>\n" );
document.write( "\n" );
document.write( "(20, 12) and (30, 15)\r<BR>\n" );
document.write( "\n" );
document.write( "if we fill in the x and y co-ordinates on the equation for a line<BR>\n" );
document.write( "y=mx+c we get teo equations which can be solves simultaneously\r<BR>\n" );
document.write( "\n" );
document.write( "15=30m+c<BR>\n" );
document.write( "12=20m+c\r<BR>\n" );
document.write( "\n" );
document.write( "minus one from the other, to get m=3/10<BR>\n" );
document.write( "fill this in into any of the two equtions to get c, whcih is 6.\r<BR>\n" );
document.write( "\n" );
document.write( "thus the realtionship, is the linear equation<BR>\n" );
document.write( "y=3/10x+6 </SPAN>\n" );
document.write( "</TD></TR></TABLE>\n" );